The present invention relates to a capsule for hygienically preparing a nutritional product containing nutritional ingredients by mixing the ingredients with a liquid; the capsule containing a filter for filtering the liquid supplied in the capsule for removing undesired components contained in the liquid. The invention more particularly relates to capsules for insertion in a device supplying liquid in the capsule for preparing a nutritional product by mixing with the nutritional ingredients such as an infant formula.
Nutritional compositions can be, for instance, infant formulas or also nutritional liquids for toddlers, invalids, elderly people, persons having nutritional deficiencies or athletes. Food compositions can be dairy-based liquids, soup, coffee or tea beverages. These compositions are prepared from ingredients contained in a capsule by addition of a liquid such as hot or ambient water. The liquid may contain undesired contaminants such as micro-organisms or solid particles. These undesired contaminants should be removed from the liquid before the liquid is mixed with the ingredients.
Therefore, there is a need for a capsule which enables preparation of nutritional composition for instance an infant formula or other food compositions in a convenient and safe manner.
WO2006/077259 discloses a method for preparing a single serving of a nutritional composition comprising introducing liquid such as water into a cartridge containing a unit dose of the composition in concentrated form. Thereby, the water is treated prior to the introduction into the cartridge in order to remove or kill pathogens from the water. This treatment may be for instance a pre-heating, a filtering or an irradiation of the water with ultra-violet light.
WO 2008/012314 relates to a device which teaches the principle of treating water by means of a filter used for the preparation of nutritional compositions from a capsule inserted in a dispenser.
A capsule with an integrated antimicrobial filter has been described in WO 2009/092629 and No. 09156782.6 filed on 31 Mar. 2009.
A problem is that the capsule may not empty completely from its content (combination of ingredients and supplied liquid). In particular, the liquid content can no longer evacuate when the supply of liquid in the capsule is stopped and the pressure in the capsule drops. In particular, the absence of air in the capsule and orifices for evacuation of the liquid content may be too small to allow emptying of the capsule. The incomplete delivery may have other causes, in particular, relative to a bad dissolution/dispersion of the ingredients in the liquid, the creation of a partial vacuum in the capsule which blocks or reduces considerably the flow out, insufficient opening of the capsule outlet, etc. If the capsule is insufficiently emptied, the nutritional dose is not properly delivered from the capsule and this may potentially cause nutritional and/or hydration issues.
Therefore, there is a need for ensuring the release of the dedicated amount of the nutritional composition contained in the capsule to ensure a complete feed for each capsule, e.g., to the baby or child. The problem is that the filter in the capsule can create a too high resistance to the pressurized gas (e.g., compressed air) injected in the capsule during the emptying operation. As a result, the pressure of gas can be insufficient to properly empty the capsule or a too high pressure of gas is required which has an impact on the complexity and cost of the system. Also if gas is forced under a too high pressure through the filter, the filter can be damaged and if so a contamination-free nutritional delivery from the capsule is no longer guaranteed.
There is also a need to ensure an hygienic contact between the device and the capsule after filtering liquid, in particular, during emptying it.